instrumental and environmental noise in geo600

Joshua Smith, Elba, Italy 31.05.06

Elba, Italy 31.05.06

Joshua Smith for the GEO 600 team

Picture of GEO in stormy weather??

Or pics of tractors with trees?

Instrumental and Instrumental and environmental noise in GEO600environmental noise in GEO600

North building

Joshua Smith, Elba, Italy 31.05.06

OverviewOverview

Environmental:o Seismico Dusto Magnetic fields / Mains

Instrumental:o Noise Projectionso Tracking couplingso Noise subtractiono Noise vetoes

A selection of recent detector characterization work

Joshua Smith, Elba, Italy 31.05.06

Seismic / up-conversionSeismic / up-conversion

H @ 240Hz

H @ 290Hz

H @ 340Hz

Seis @ 49Hz

0 Time [h] 3.5

Am

plit

ude

(max

)

Joshua Smith, Elba, Italy 31.05.06

DustDust

Joshua Smith, Elba, Italy 31.05.06

Power glitchesPower glitches

Detector output

Input port power

Joshua Smith, Elba, Italy 31.05.06

Back-coupling?Back-coupling?

Strain coupling to DC power

Dark port DC Power

Strain back-coupling doesn’t explain instrumental channel coincidence

Joshua Smith, Elba, Italy 31.05.06

Power glitches vs. dustPower glitches vs. dust

Dark port DC power glitch count

Dark port DC power glitch count

Particle count

Dark port DC power glitch count

Input port DC power glitch count

0 Time [m] 180

Joshua Smith, Elba, Italy 31.05.06

Particle waves filteredParticle waves filtered14020

455

30.2

(Par

ticl

es/c

u.ft

)/10

00

A

a

Joshua Smith, Elba, Italy 31.05.06

Dust made loudest glitchesDust made loudest glitches

Before filter After filter

Time [h] Time [h]Det. output BLRMS @~ 170Hz

Joshua Smith, Elba, Italy 31.05.06

Magnetic fields / MainsMagnetic fields / Mains

Joshua Smith, Elba, Italy 31.05.06

Magnetic field glitchesMagnetic field glitches

B glitches H glitches

Linear coupling, coherence

Joshua Smith, Elba, Italy 31.05.06

Magnetic field “projection”Magnetic field “projection” B-field nearly limiting noise around 100Hz?

o Coupling not yet understood o Checks: magnetometer measures B-field, IFO back-coupling ruled out

Joshua Smith, Elba, Italy 31.05.06

Hourly mains glitchesHourly mains glitches

Hourly series start:o 24 secs after GPS houro 10 secs after UTC hour

24s

Joshua Smith, Elba, Italy 31.05.06

Mag./mains coinc. with HMag./mains coinc. with H

Fr e

quen

c y [

Hz]

Magnetometer central building ~ 50coinc./8hrs

Time-freq glitch maps

Time-shifted coincidence

Mains monitor central building ~ 30coinc./8hrs

Time [h] Time [h]0 08 8

50

0

50

0

Time shift [s] Time shift [s]1 1-1 -1

Fre

quen

c y [

Hz]

Joshua Smith, Elba, Italy 31.05.06

Noise ProjectionsNoise Projections

Joshua Smith, Elba, Italy 31.05.06

Noise BudgetNoise Budget

Alignment actuation

Scattering, up-conversion, ? Shot, dark, osc. phase

Joshua Smith, Elba, Italy 31.05.06

Tracking noise transfer func’sTracking noise transfer func’s

Tracked:

Signal Recycl. FB

Osc. Phase

Laser intensity

Frequency

Amp ratio ~ 1

phase diff ~ 0

Joshua Smith, Elba, Italy 31.05.06

Transfer func’s: long-term (10d)Transfer func’s: long-term (10d)

10 days, most projections:

+/- 10% mag

+/- 10 degs phase

So, long-term stable

Ratio/Diffs drifts

Histogram of drifts

Joshua Smith, Elba, Italy 31.05.06

Noise transfer func’s: short-termNoise transfer func’s: short-term

+/- 20% mag. variations on second timescales!

Joshua Smith, Elba, Italy 31.05.06

Noise SubtractionNoise Subtraction

Joshua Smith, Elba, Italy 31.05.06

Detector output and noiseDetector output and noise

Detector output

Noise chans.

Record subset

Noise projection

Noise budget

Improved H

Joshua Smith, Elba, Italy 31.05.06

Noise subtraction requirementsNoise subtraction requirements

Subtraction factor depends on amplitude ratio and phase difference of filter used and real transfer function response.

Joshua Smith, Elba, Italy 31.05.06

Noise subtraction resultsNoise subtraction results

Time domain subtraction, simple IIR filters fit to measured TF response.

Ratio H/(H-Projs)

But, no reduction of up-conversion

Joshua Smith, Elba, Italy 31.05.06

Technical noise vetoTechnical noise veto

Joshua Smith, Elba, Italy 31.05.06

Noise veto: eg. injectionNoise veto: eg. injection

H

Michelson oscillator phase noise

Joshua Smith, Elba, Italy 31.05.06

Noise veto performanceNoise veto performance

“Robust vetoes for gravitational-wave burst triggers using known instrumental couplings”

P. Ajith, M. Hewitson, J. R. Smith, K. A. Strain, submitted to CQG, http://arxiv.org/abs/gr-qc/0605079

Estimated veto efficiency vs. rejection probability

for the chosen thresholds.

Joshua Smith, Elba, Italy 31.05.06

The endThe end

'falco tinnunculus',

better know as 'Turmfalke'

Joshua Smith, Elba, Italy 31.05.06

Noise subtraction IINoise subtraction II

Used simple IIR filters

- good match to simple transfer function

Joshua Smith, Elba, Italy 31.05.06

Statistical dust veto?Statistical dust veto?

MID VIS veto TF map and timeshifted results